Should I move on from him? Is he interested in me?

I have his guy whom I have known for over a year now. We talk to eachother every time we see eachother. We work together and are both going to the same college. He works two jobs, and is a full time student. I work one part time job and go to school full time. We've gone out to lunch a few times but he has yet to ask me out. I've asked him to go those times we've gone out. We click and get along great and he seems interested in me. He says he can't hangout because he is busy with school and work. Is this his way of saying he's not interested in me, or is he really just busy and does like me. There is no awkwardness whatsoever and he's always very sweet to me. He holds doors open for me and asks how I am. I just can't read his signals. I really like him. Help!